Geometry Chart

If you feel like you've got too much on your head when you're riding, try a lighter helmet. Giro's Prolight helmet is a race-level helmet that presents the new standard for lightweight and streamlined design. It has a superlight In-Mold shell with 25 aerodynamic vents to channel maximum airflow over your head. It also sports the Roc Loc SL fit system with Super Fit sizing, so you create a fit that is so custom, you'll barely feel the helmet at all.

In-Mold construction provides strength, integrity and is so lightweight, you'll have to remind yourself that you've got a helmet on at all

25 Wind Tunnel vents with fully optimized internal channels thrust cool, fresh air over and around your head while forcing heat and stale air out

I purchased this helmet for my husband. He is an active road cyclist. The helmet was light weight as indicated. However, the fore/aft system adjustment was very flimsy and looked like it would not be very durable for regular riding. We returned it.

As I've seen in other reviews, this helmet felt "tippy" on my head, and didn't feel secure. I wanted the feeling of "it feels like there's nothing on your head", and it is very very light. I was ready for the very spare adjustment system, but it just didn't give me a feeling of security. My head measures 23.25" which I thought would give me a nice close fit with the Medium. It fit front to back, but with gaps around the the sides. For some who happen to have the right shaped head, they might like it, but it wasn't for me. I think the new Giro Aeon (slightly heavier) might have worked out these problems, but it's really expensive. For now, I'm going back to my trusty old Giro Transfer that I got years ago for twenty bucks (yes, TWENTY BUCKS!!). Being a low cost helmet, it comes as a "one size fits all", but for me it's a better fit. Despite the little bit of extra weight, it was almost a relief to put on after trying to get comfy with the Prolight. I reluctantly sent the Prolight back.

This helmet replaced an older Giro helmet. I am impressed with the light weight and comfort of the helmet. It was easy to adjust, but you had to figure that out on your own as the documentation in the manual was lacking.

I used this on longer rides and in hot weather. I hit cinders in Flagstaff and endoed at about 20 mph. Helmet hit hard but stayed in place, probably saved my life. Broken in several places and dented but did its job. Will buy another.